Extracts obtained from plants of Orchidaceae have hitherto been used in cosmetics or the like, since such extracts have moisturizing effect, skin-conditioning effect, skin-whitening effect, anti-aging effect on the skin, or the like. For example, the following patent documents, i.e. JP-A-2007-008911, JP-A-2007-077079, JP-A-2006-282536, JP-A-2005-179219, JP-A-2004-067549, JP-A-2002-205933, JP-A-2002-003336, Japanese Patent No. 3526590, Japanese Patent No. 3090156, JP-A-H2-279618 (1990), and JP-A-S57-102809 (1982), disclose cosmetics, skin-moisturizing agents, and skin external agents containing extracts obtained from plants of Orchidaceae.
As plants of Orchidaceae used for obtaining extracts, the aforementioned patent documents disclose, for example, Gymnadenia (JP-A-2007-077079), Cattleya (JP-A-2006-282536, JP-A-2004-067549), Calanthe, Phaius (JP-A-2005-179219), Bletilla striata, Cephalanthera falcata, Cremastra appendiculata, Cymbidium goeringii, Dactylorhiza aristata, Dendrobium moniliforme, Epipactis thunbergii, Galeola septentrionalis, Gastrodia elata, Neottia nidusavis, Orchis, Vanilla fragrans (JP-A-2002-205933), Cymbidium (JP-A-2002-003336), Dactylorhiza, Cephalanthera, Neottia, Epipactis (Japanese Patent No. 3526590), Phalaenopsis (Japanese Patent No. 3090156), Dendrobium, Cattleya, Cymbidium, Cymbidium goeringii (JP-A-H2-279618 (1990)), and Bletilla striata (JP-A-S57-102809 (1982)).
It is said that 20,000 or more plant species of Orchidaceae exist, and the Orchidaceae family is the largest family of angiosperms, accounting for approximately 10% thereof. The area of distribution extends from the tropical region to the frozen region, and plants of Orchidaceae grow in every environment, except for extremely dry regions. Thus, such plants are very diversified in terms of ecological and morphological properties, and there are many theories regarding the lineages and classifications of plants of Orchidaceae (“Sekai no Chinran Kiran daizukan,” Seibundo Shinkosha, Japan, 2006). Thus, plants of Orchidaceae that belong to the different genera differ from one another in terms of morphologies, such as flowers, leaves, stems, and roots. Also, it can be easily deduced that components of extracts therefrom differ from one another.
Examples of natural polysaccharides that are known to be used as moisturizing agents include polysaccharides derived from animals, such as hyaluronic acid, and polysaccharides derived from plants, such as quince, Tremella fuciformis, and aloe (FRAGRANCE JOURNAL, Japan, March 2005). Also, the patent documents mentioned above state that polysaccharides are contained in extracts obtained from plants of Orchidaceae; i.e., Cymbidium (JP-A-2002-003336), Dendrobium, Cattleya, Cymbidium, Cymbidium goeringii rhizomes (JP-A-H2-279618 (1990)), and Bletilla striata tubers (JP-A-S57-102809 (1982)), and they also state that such polysaccarides have moistening effects. It is generally known that a polysaccharide is composed of many monosaccharides linked via glycoside linkages, there are many types of polysaccharides, and natural polysaccharides differ from each other in terms of sugar compositions, structures, molecular weights, and the like, depending on their origins. For example, hyaluronic acid is a linear polysaccharide polymer composed of alternately linked N-acetylglucosamine and glucuronic acid, a Tremella fuciformis polysaccharide is an acidic heteropolysaccharide mainly composed of mannose, xylose, and glucuronic acid, a polysaccharide extracted from the quince epidermis is an acidic heteropolysaccharide in which arabinose, xylose, or uronic acid is linked (FRAGRANCE JOURNAL, Japan, March 2005), an aloe polysaccharide is a heteropolysaccharide comprising mannose, galactose, and glucose at 11:0.2:1 (“Modified Aloe barbadensis Polysaccharide with Immunoregulatory Activity,” Plant Medica, 66, 152-156, 2000), and a polysaccharide extracted from Bletilla striata tubers (i.e., Bletilla-glucomannan) is a heteropolysaccharide comprising mannose and glucose at 3:1 (“Plant Mucilages. VIII. Isolation and Characterization of a Mucous Polysaccharide, “Bletilla-glucomannan,” from Bletilla striata Tubers.,” Chem. Pharm. Bull. 21 (12) 2667-2671, 1973). Regarding polysaccharides derived from the plants of Orchidaceae, there is no description other than Bletilla-glucomannan contained in tubers of Bletilla striata, and details thereof have not yet been elucidated.
In addition to the plants of Orchidaceae, ivory palm, guar, Ceratonia siliqua, tara, and the like are listed as plants containing large quantities of mannan compounds. It is known that mannan compounds contained in the extracts of mannan compounds are subjected to acidic hydrolysis from the above plants to produce mannose (JP-A-2000-70000).